1. Field of the Invention
Embodiments of the present invention generally relate to apparatus and processes for performing thin-film panel edge deletion on a solar cell device in a solar cell production line.
2. Description of the Related Art
Photovoltaic (PV) devices or solar cells are devices which convert sunlight into direct current (DC) electrical power. Typical thin film PV devices, or thin film solar cells, have one or more p-i-n junctions. Each p-i-n junction comprises a p-type layer, an intrinsic type layer, and an n-type layer. When the p-i-n junction of the solar cell is exposed to sunlight (consisting of energy from photons), the sunlight is converted to electricity through the PV effect. Solar cells may be tiled into larger solar arrays. The solar arrays are created by connecting a number of solar cells and joining them into panels with specific frames and connectors.
Typically, a thin film solar cell includes active regions, or photoelectric conversion units, and a transparent conductive oxide (TCO) film disposed as a front electrode and/or as a back electrode. The photoelectric conversion unit includes a p-type silicon layer, an n-type silicon layer, and an intrinsic type (i-type) silicon layer sandwiched between the p-type and n-type silicon layers. Several types of silicon films including microcrystalline silicon film (μc-Si), amorphous silicon film (a-Si), polycrystalline silicon film (poly-Si), and the like may be utilized to form the p-type, n-type, and/or i-type layers of the photoelectric conversion unit. The backside electrode may contain one or more conductive layers.
With traditional energy source prices on the rise, there is a need for a low cost way of producing electricity using a low cost solar cell device. Conventional solar cell fabrication processes include a number of inefficient operations that lead to unacceptable production line downtime. Seaming and edge deletion are standard operations necessary for the fabrication of solar cells. This process provides electrical separation of the active cells in a solar module as well as electrical isolation and sealing from the outside environment by removing the conductive layers along the edge of the solar cell module. Conventional edge deletion techniques are performed with a belt sanding mechanism. Edge deletion by belt sanding is adequate, but the life of the belts themselves is unacceptably short, resulting in frequent maintenance intervals. Excessive consumption of sanding belts is due, in part, to the tendency of abraded material to collect and adhere to the abrasive surface of the belt, a problem which is inherent to most, if not all, abrading mechanisms and techniques. This, of course, results in high maintenance costs, excessive downtime, poor throughput, and ultimately, high solar cell cost. Accordingly, a need exists for a seaming and edge deletion module that is reliable, efficient, and easily maintained.